%I Automatic Control Laboratory, ETH, Zurich %N %X This is the HYSDEL user guide. HYSDEL allows to model a class of hybrid systems described by interconnections of linear dynamic systems, automata, if-then-else and propositional logic rules. For this class of systems we present general techniques for transforming an abstract representation into a set of constrained linear difference equations involving integer and continuous variables. The resulting model can be immediately used for optimization, to solve, e.g., optimal control problems or as an intermediate step to obtain other popular representations such as piecewise a?ne systems. The developer's manual [39] completes the present document with the details on the implementation of HYSDEL and is included in the source distribution. %D 2002 %L eprints2257 %T HYSDEL 2.0. 5- User manual %A Fabio Danilo Torrisi %A Alberto Bemporad %A Gioele Bertini %A Peter Hertach %A Dominic Jost %A Domenico Mignone